Ogham is an early medieval script in which letters are represented by groups of notches and lines cut along the edge of a stone, and the Ballyknock group represents one of the more striking concentrations of such monuments found in Ireland. That these inscribed stones were repurposed as structural material tells us something about how later generations related to, or simply failed to recognise, the significance of what was already in the ground beneath them.

One stone from the group, measuring just over four feet in length, was lifted and examined in the nineteenth century by the Reverend E. Barry, who published his reading of the inscription in 1890 as BLATEGSI, most likely a personal name in the genitive case, meaning roughly "of Blateg" or similar. Barry replaced the stone after examination. When the scholar R. A. S. Macalister returned to the inscription in 1945, he read it differently as BLOTEGSI, a small but meaningful divergence. Barry, however, had an explanation: an extra notch that altered the reading had been made accidentally by crowbar damage during the original lifting, and was not part of the ancient inscription at all. The stone was recorded as having been moved to Lismore Castle in County Waterford in 1920, where it may or may not still reside; its current whereabouts have never been confirmed with certainty.